In accordance with new Harvard policies regarding gatherings over 25 people, this talk has been CANCELLED. Learn more about the campus' response to the coronavirus here: https://www.harvard.edu/coronavirus

A Harvard-China Project Research Seminar with Jianxiong Sheng, Research Scientist, Center for Global Change Science, MIT

Abstract: China’s methane emissions are the largest anthropogenic source in the global methane budget according to the recent UNFCCC reports. However, China’s emissions are poorly quantified. Here we use 2010-2017 GOSAT satellite observations of methane columns in a top-down (inverse modeling) analysis to improve the estimates of China’s methane emissions and trends. Our inversion uses a Lagrangian particle dispersion model as the forward model (~30 km resolution) and optimizes emissions under a Bayesian framework with full error characterization. Our inversion uses WETCHART v1.2 for natural wetlands and EDGAR v4.3.2 for anthropogenic sources, except for oil/gas and coal mining sectors that we replace with state-of-the-art emission inventories having more accurate emission patterns (Sheng et al., 2019; Scarpelli et al., 2020). Our inversion results show that total anthropogenic methane emissions (54-60 Tg/a) in China are comparable to those reported in UNFCCC and the emissions trend from 2010 to 2017 has significantly slowed as compared to that before 2010. Our results also suggest that China’s coal mine methane emissions have been stable since 2012, consistent with its coal mining activities, while the increasing national trend is likely due to agriculture/waste.

Dr. Jianxiong Sheng is a research scientist with Prof. Ronald Prinn working on inverse modeling of trace gases as part of the AGAGE project. Previously he was a postdoc at Harvard with Prof. Daniel Jacob working to better understand methane emissions in North America through inversions of aircraft and satellite observations. He is very much an international man of science. Born in Shanghai China, his academic career in the sciences has taken him around the world. As an undergraduate he studied math in Belgium, which laid the foundation for a master’s in fluid mechanics in Paris, which in turn set the stage for a PhD in environmental science in Zurich.

Sponsored by Harvard-China Project, Harvard Paulson School of Engineering and Applied Sciences.